unicode-bidi (CSS property)

Spec
Inherited Initial Version
No normal CSS2
Browser support (more…)
IE8+ FF1+ SA1.3+ OP9.2+ CH2+
Full Full Full Full Full

Syntax

unicode-bidi: { bidi-override | embed | normal | inherit } ;

Description

Along with direction, this property relates to the handling of bidirectional text within a given document. If a paragraph contains both left-to-right text and right-to-left text, the user agent applies a complex algorithm defined by the Unicode standard to determine how the text should appear. This property specifically controls the embedding levels and overrides for the Unicode bidirectional algorithm.

The CSS2.1 specification emphasizes that this property should normally be used only by DTD designers. In particular, authors, web designers, and users shouldn’t override it.

Example

This style rule creates a new embedding level with a right-to-left writing direction for bible-quote elements (assumed to be in Hebrew) in an XML document:

bible-quote {
  direction: rtl;
  unicode-bidi: embed;
}

Value

bidi-override
This value creates an override for inline elements. For block-level elements, table cells, table captions, or inline blocks, it creates an override for (some) inline-level descendants. In other words, the implicit part of the bidirectional algorithm is ignored and the value of the direction property is used for reordering content within the element.
embed
This value offers an additional level of embedding for inline elements. The direction of the embedding level is determined by the direction property.
normal
This value doesn’t offer an additional level of embedding with respect to the bidirectional algorithm. For inline elements, implicit reordering works across element boundaries.

Compatibility

Internet Explorer Firefox Safari Opera Chrome
5.5 6.0 7.0 8.0 1.0 1.5 2.0 3.0 3.5 1.3 2.0 3.1 4.0 9.2 9.5 10.0 2.0
Buggy Buggy Buggy Full Full Full Full Full Full Full Full Full Full Full Full Full Full

Internet Explorer for Windows versions up to and including 7 have some serious bugs relating to floated elements used in combination with the declarations direction: rtl; and unicode-bidi: embed;.

Internet Explorer for Windows versions up to and including 7 don’t support the value inherit.

A series of tests on browser support for direction and unicode-bidi can be found at the WC3 site.

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